Police shouldn't be able to search suspects' mobile phones at the time of arrest because of the huge amounts of private information now stored on those devices, lawyers for two criminal defendants argued before U.S. Supreme Court Tuesday.

The Supreme Court should make an exception for mobile phones in long-standing case law allowing police officers to search suspects at the time of the arrest without getting a court-ordered warrant, lawyers for the two defendants argued.

If the court allows uninhibited police searches of smartphones, it has "fundamentally changed the idea" that warrants are needed to search most personal effects, said Jeffrey Fisher, a lawyer representing David Riley, who was arrested on gang-related charges in San Diego in 2009. A smartphone potentially contains much more personal information than a suspect could carry in the predigital era, he said.

Several justices seemed to be sympathetic to the arguments for Riley, if not for Brima Wurie, a suspected drug dealer arrested in Boston in 2007.

The state of California's position that police should be allowed wide latitude to search suspects' mobile phones at the time of arrest opens up the possibility of privacy-invading searches of photographs, medical records, email, phone records and GPS records after arrests for minor infractions, said Justice Elena Kagan.

"A person can be arrested for anything," she said. "A person can be arrested for driving without a seat belt."

Other justices questioned why they should prohibit police from searching mobile phones, when they already can search a suspect's wallet or cigarette pack. Under current case law, police could search a piece of paper in a suspect's pocket that contains phone numbers, said Justice Samuel Alito.

The difference is one of scale, Fisher said. Smartphone users increasingly have their "entire lives" on their devices, he said.

Kagan agreed. A search of a suspect's smartphone has much broader privacy implications than "when people have pictures of their family in their billfolds," she said.

California Solicitor General Edward DuMont and U.S. Deputy Solicitor General Michael Dreeben called on the court to allow police searches of mobile phones at the time of the arrest. Police must have those search powers to investigate the crimes the suspects were arrested for, to protect themselves against bombs or other weapons hidden in phones and to prevent the suspect from calling or texting friends with a request to attack the arresting officers, they said.

In addition, police are becoming increasingly concerned about encryption on phones, Dreeben said. In some cases, if a smartphone is allowed to lock, it may be difficult for police to break the password or to defeat encryption on the phone, he said. "It may be months or years or never that they can break through the encryption," he said.

Judith Mizner, a federal public defender for Wurie, suggested the encryption and password concerns were overblown. She questioned how many times police arrest a suspect holding an unlocked mobile phone. In her client's case, police searched his flip phone after he was taken to a station, she noted.

When Fisher and Mizner argued that police shouldn't be able to search mobile phones without a warrant unless there are so-called "exigent circumstances" such as immediate injury, some justices questioned how police could decide what amounts to an exigent circumstance. They also called on the court to allow only limited searches of phones through warrants, instead of allowing police to "rummage" through phones, as Mizner phrased it.

Chief Justice John Roberts questioned how a judge could determine what information on a phone was fair game. "What part of a smartphone is not likely to have potential evidence?" he asked.

In the Riley case, San Diego police pulled him over for driving with expired tags. During a search of the car, police found two guns under the car's hood and they found a smartphone in Riley's pocket. Officers at the scene found what they believed to be evidence of gang affiliation on Riley's smartphone, then, in a later search of the phone, found pictures of Riley making gang hand signals and pictures of a car they believed to be involved in an earlier gang shooting.

The picture of the car, along with ballistic tests connecting Riley to the earlier shooting, led police to charge him in the shooting. Riley's lawyers tried to get the smartphone evidence thrown out, saying it violated the U.S. Constitution Fourth Amendment's prohibition against unreasonable searches and seizures. A California court rejected that effort, and Riley was convinced on three charges, including shooting at an occupied vehicle.

In the second case, police observed what they suspected to be a drug deal and arrested suspect Wurie after he drove away from the scene. After Wurie arrived at the police station, police found a call log on his flip phone and traced a number designated as "my house." After connecting that number to a street address, police obtained a warrant, searched the house and found crack cocaine, marijuana, a gun and ammunition.

Wurie's lawyers filed a motion to suppress the evidence obtained through the warrantless search of his mobile phone, and a judge denied the motion. After Wurie was convicted on three counts, including intent to distribute and distributing cocaine base, the defendant appealed the case, and an appeals court threw out the conviction.

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's email address is grant_gross@idg.com.

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